sat-solver/BoxedVec.h

/*******************************************************************************************[Vec.h]
MiniSat -- Copyright (c) 2003-2006, Niklas Een, Niklas Sorensson

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**************************************************************************************************/

#ifndef BoxedVec_h
#define BoxedVec_h

#include <cstdlib>
#include <cassert>
#include <new>

//=================================================================================================
// Automatically resizable arrays
//
// NOTE! Don't use this vector on datatypes that cannot be re-located in memory (with realloc)

template<class T>
class bvec {

    static inline int imin(int x, int y) {
        int mask = (x-y) >> (sizeof(int)*8-1);
        return (x&mask) + (y&(~mask)); }

    static inline int imax(int x, int y) {
        int mask = (y-x) >> (sizeof(int)*8-1);
        return (x&mask) + (y&(~mask)); }

    struct Vec_t {
        int sz;
        int cap;
        T   data[0];

        static Vec_t* alloc(Vec_t* x, int size){
            x = (Vec_t*)realloc((void*)x, sizeof(Vec_t) + sizeof(T)*size);
            x->cap = size;
            return x;
        }
        
    };

    Vec_t* ref;

    static const int init_size = 2;
    static int   nextSize (int current) { return (current * 3 + 1) >> 1; }
    static int   fitSize  (int needed)  { int x; for (x = init_size; needed > x; x = nextSize(x)); return x; }

    void fill (int size) {
        assert(ref != NULL);
        for (T* i = ref->data; i < ref->data + size; i++)
            new (i) T();
    }

    void fill (int size, const T& pad) {
        assert(ref != NULL);
        for (T* i = ref->data; i < ref->data + size; i++)
            new (i) T(pad);
    }

    // Don't allow copying (error prone):
    altvec<T>&  operator = (altvec<T>& other) { assert(0); }
    altvec (altvec<T>& other)                  { assert(0); }

public:
    void     clear  (bool dealloc = false) { 
        if (ref != NULL){
            for (int i = 0; i < ref->sz; i++) 
                (*ref).data[i].~T();

            if (dealloc) { 
                free(ref); ref = NULL; 
            }else 
                ref->sz = 0;
        } 
    }

    // Constructors:
    altvec(void)                   : ref (NULL) { }
    altvec(int size)               : ref (Vec_t::alloc(NULL, fitSize(size))) { fill(size);      ref->sz = size; }
    altvec(int size, const T& pad) : ref (Vec_t::alloc(NULL, fitSize(size))) { fill(size, pad); ref->sz = size; }
   ~altvec(void) { clear(true); }

    // Ownership of underlying array:
    operator T*       (void)           { return ref->data; }     // (unsafe but convenient)
    operator const T* (void) const     { return ref->data; }

    // Size operations:
    int      size   (void) const       { return ref != NULL ? ref->sz : 0; }

    void     pop    (void)             { assert(ref != NULL && ref->sz > 0); int last = --ref->sz; ref->data[last].~T(); }
    void     push   (const T& elem) {
        int size = ref != NULL ? ref->sz  : 0;
        int cap  = ref != NULL ? ref->cap : 0;
        if (size == cap){
            cap = cap != 0 ? nextSize(cap) : init_size;
            ref = Vec_t::alloc(ref, cap); 
        }
        //new (&ref->data[size]) T(elem); 
        ref->data[size] = elem; 
        ref->sz = size+1; 
    }

    void     push   () {
        int size = ref != NULL ? ref->sz  : 0;
        int cap  = ref != NULL ? ref->cap : 0;
        if (size == cap){
            cap = cap != 0 ? nextSize(cap) : init_size;
            ref = Vec_t::alloc(ref, cap); 
        }
        new (&ref->data[size]) T(); 
        ref->sz = size+1; 
    }

    void     shrink (int nelems)             { for (int i = 0; i < nelems; i++) pop(); }
    void     shrink_(int nelems)             { for (int i = 0; i < nelems; i++) pop(); }
    void     growTo (int size)               { while (this->size() < size) push(); }
    void     growTo (int size, const T& pad) { while (this->size() < size) push(pad); }
    void     capacity (int size)             { growTo(size); }

    const T& last  (void) const              { return ref->data[ref->sz-1]; }
    T&       last  (void)                    { return ref->data[ref->sz-1]; }

    // Vector interface:
    const T& operator [] (int index) const  { return ref->data[index]; }
    T&       operator [] (int index)        { return ref->data[index]; }

    void copyTo(altvec<T>& copy) const { copy.clear(); for (int i = 0; i < size(); i++) copy.push(ref->data[i]); }
    void moveTo(altvec<T>& dest) { dest.clear(true); dest.ref = ref; ref = NULL; }

};


#endif